This invention relates to the field of transfer ribonucleic acid (tRNA) synthetase inhibitors, their preparation and their use as antimicrobial agents.
Aminoacyl tRNA synthetases (aaRS) are a family of essential enzymes that are found in virtually every biological cell and are responsible for maintaining the fidelity of protein synthesis. They specifically catalyze the aminoacylation of tRNA in a two step reaction:
amino acid (AA)+ATP= greater than AA-AMP+PPi
AA-AMP+tRNA= greater than tRNA-AA+AMP
The enzyme binds adenosine triphosphate (ATP) and its specific amino acid to catalyze formation of an aminoacyl adenylate complex (AA-AMP) with concomitant release of pyrophosphate (PPi). In the second step, the amino acid is transferred to the 2xe2x80x2 or 3xe2x80x2 terminus of the tRNA yielding xe2x80x9cchargedxe2x80x9d tRNA and adenosine monophosphate (AMP). The charged tRNA delivers the amino acid to the nascent polypeptide chain on the ribosome.
There are at least twenty essential enzymes in this family for each organism. Inhibition of any of the essential tRNA synthetases disrupts protein translation, ultimately resulting in growth inhibition. Pseudomonic acid A, an antibacterial agent currently used in human therapy, provides clear evidence of the utility of tRNA synthetase inhibitors as useful pharmaceuticals. Pseudomonic acid A binds to one particular tRNA synthetase, isoleucyl tRNA synthetase, and inhibits isoleucyl adenylate formation in several Gram positive bacterial pathogens such as Staphylococcus aureus, resulting in the inhibition of protein synthesis, followed by growth inhibition.
Novel synthetic compounds that target tRNA synthetases offer clear advantages as useful therapeutic agents to curb the threat of drug resistance. Drug resistance allows a pathogen to circumvent the biochemical disruption caused by an antimicrobial agent. This resistance can be a result of a mutation that has been selected for and maintained. Pathogens in the environment have had repeated exposure to current therapeutics. This exposure has led to the selection of variant antimicrobial strains resistant to these drugs. Novel synthetic antimicrobial agents, therefore, would be expected to be useful to treat drug resistant pathogens, since the pathogen has never been exposed to the novel antimicrobial agent. The development of compounds or combinations of compounds targeting more than one tRNA synthetase is also advantageous. Accordingly, inhibition of more than one enzyme should reduce the incidence of resistance since multiple mutations in a pathogen would be required and are statistically rare.
The present invention discloses novel compounds which inhibit tRNA synthetases and have efficacy, including whole cell killing, against a broad spectrum of bacteria and fungi. Described herein are compounds that exhibit tRNA synthetase inhibition.
The present invention comprises, in one aspect, compounds of Formula I. 
Group Ar of Formula I is selected from aryl or heteroaryl. Preferably, Ar is aryl, more preferably, substituted phenyl, even more preferably, 2,4-dichlorophenyl.
Each of substituents R1, R2, R3, and R4 of Formula I is independently hydrido, alkyl, cyano, heteroaryl, hydroxy, amino, acylamino, halo, alkoxy, aryloxy, carboxyamido, alkenyl, cycloalkyl, heterocyclyl, acyl, acyloxy, carboalkoxy, carboxy, thio, sulfinyl, sulfonyl or sulfoxy, provided that at least two of R1, R2, R3 and R4 is hydrido. Preferably, each of substituents R1, R2, R3 and R4 is independently selected from hydrido, carboxyl, alkyl, carboxyamido, N-acylaminosulfonyl, N-sulfonylcarboxyamido, and alkoxy. More preferably, each of substituents R1, R2, R3 and R4 is independently selected from xe2x80x94(CH2)mCO2Hxe2x80x94, xe2x80x94(CH2)mCONHCH(R9)CO2Hxe2x80x94, xe2x80x94CONHSO2R10xe2x80x94, and xe2x80x94O(CH2)mCO2H; wherein each of R9 and R10 is independently selected from alkyl and halo substituted alkyl; wherein m is selected from 0, 1 and 2.
Each of substituents R5, R6, R7 and R8 is independently hydrido or lower alkyl, preferably hydrido.
Group Het of Formula I is selected from 
wherein X is selected from N or CR11; wherein Y is selected from NH, S or O; wherein Z is selected from N or CR12; wherein each of R11, R12, R13, and R14 is independently selected from nitro, halo, hydroxy, lower amino, lower alkyl, lower alkoxy, aryloxy, lower carboalkoxy, sulfinyl, sulfonyl, carboxy, lower thio, and sulfoxy; and wherein each of R15, R16, and R17 is selected from hydrido, alkyl, aryl, nitro, amino, sulfonyl or sulfinyl. Preferably, Het is 
The invention also embraces pharmaceutically-acceptable salts of the forgoing compounds.
A further aspect of the invention comprises using a composition comprising the compound(s) of Formula I to inhibit a tRNA synthetase and in particular, to modulate the growth of bacterial or fungal organisms in mammals, a plant or a cell culture.
Yet another aspect of the invention involves a method of inhibiting the growth of microorganisms. The method involves exposing the microorganism to a compound of the invention, preferably a compound of Formula I, under conditions whereby a therapeutically effective amount of the compound enters the microorganism. The method is useful for inhibiting the growth of microrganisms in vivo and in vitro.
Another aspect of the invention is a pharmaceutical composition comprising the compound(s) of the invention and, in particular, the compounds of Formula I, useful in the treatment of microbial infections, e.g., bacterial infections, fungal infections. A related aspect of the invention is a method of making a medicament which involves placing a compound(s) of the invention, preferably a compound of Formula I, in a suitable pharmaceutically acceptable carrier.
These and other aspects of the invention will be more apparent in reference to the following detailed description of the invention.
I. Definitions
Molecular terms, when used in this application, have their common meaning unless otherwise specified. The term xe2x80x9chydridoxe2x80x9d denotes a single hydrogen atom (H). The term xe2x80x9cacylxe2x80x9d is defined as a carbonyl radical attached to a hydrido, alkyl, alkenyl, alkynyl, cycloalkyl, heterocycyl, aryl or heteroaryl group, examples of such radicals being formyl, acetyl and benzoyl. The term xe2x80x9caminoxe2x80x9d denotes a nitrogen radical containing two substituents independently selected from the group consisting of hydrido, alkyl, cycloalkyl, heterocyclyl, aryl, and heteroaryl. Preferred amino radicals are NH2 radicals and xe2x80x9clower aminoxe2x80x9d radicals, whereby the two substituents are independently selected from hydrido and lower alkyl. A subset of amino is xe2x80x9calkylaminoxe2x80x9d, whereby the nitrogen radical contains at least 1 alkyl substituent. Preferred alkylamino groups contain alkyl groups that are substituted, for example, with a carboalkoxy group. The term xe2x80x9cacyloxyxe2x80x9d denotes an oxygen radical adjacent to an acyl group. The term xe2x80x9cacylaminoxe2x80x9d denotes a nitrogen radical adjacent to an acyl, carboalkoxy or carboxyamido group. The term xe2x80x9ccarboalkoxyxe2x80x9d is defined as a carbonyl radical adjacent to an alkoxy or aryloxy group. The term xe2x80x9ccarboxyamidoxe2x80x9d denotes a carbonyl radical adjacent to an amino group. A subset of carboxyamido is xe2x80x9cN-sulfonylcarboxyamidoxe2x80x9d which denotes a carbonyl radical adjacent to an N-sulfonyl-substituted amino group. The term xe2x80x9chaloxe2x80x9d is defined as a bromo, chloro, fluoro or iodo radical. The term xe2x80x9cthioxe2x80x9d denotes a sulfur radical adjacent to a substituent group selected from hydrido, alkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl, such as, methylthio and phenylthio. Preferred thio radicals are xe2x80x9clower thioxe2x80x9d radicals containing lower alkyl groups.
The term xe2x80x9calkylxe2x80x9d is defined as a linear or branched, saturated radical having one to about ten carbon atoms unless otherwise specified. Preferred alkyl radicals are xe2x80x9clower alkylxe2x80x9d radicals having one to about five carbon atoms. One or more hydrogen atoms can also be replaced by a substitutent group selected from acyl, amino, acylamino, acyloxy, carboalkoxy, carboxy, carboxyamido, cyano, halo, hydroxy, nitro, thio, alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, alkoxy, aryloxy, sulfoxy, sulfinyl, sulfonyl, N-sulfonylcarboxyamido, and N-acylaminosulfonyl. Preferred substituents are carboalkoxy, carboxy, N-sulfonylcarboxyamido, and N-acylaminosulfonyl. Examples of alkyl groups include methyl, tert-butyl, isopropyl, methoxymethyl, carboxymethyl, and carbomethoxymethyl. The term xe2x80x9calkenylxe2x80x9d embraces linear or branched radicals having two to about twenty carbon atoms, preferably three to about ten carbon atoms, and containing at least one carbon-carbon double bond. One or more hydrogen atoms can also be replaced by a substituent group selected from acyl, amino, acylamino, acyloxy, carboalkoxy, carboxy, carboxyamido, cyano, halo, hydroxy, nitro, thio, alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, alkoxy, aryloxy, sulfoxy, sulfinyl, sulfonyl, N-sulfonylcarboxyamido, and N-acylaminosulfonyl. Examples of alkenyl groups include ethylenyl or phenyl ethylenyl. The term xe2x80x9calkynylxe2x80x9d denotes linear or branched radicals having from two to about ten carbon atoms, and containing at least one carbon-carbon triple bond. One or more hydrogen atoms can also be replaced by a substituent group selected from acyl, amino, acylamino, acyloxy, carboalkoxy, carboxy, carboxyamido, cyano, halo, hydroxy, nitro, thio, alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, alkoxy, aryloxy, sulfoxy, sulfinyl, sulfonyl, N-sulfonylcarboxyamido, and N-acylaminosulfonyl. Examples of alkynyl groups include propynyl. The term xe2x80x9carylxe2x80x9d denotes aromatic radicals in a single or fused carbocyclic ring system, having from five to twelve ring members. One or more hydrogen atoms may also be replaced by a substituent group selected from acyl, amino, acylamino, acyloxy, carboalkoxy, carboxy, carboxyamido, cyano, halo, hydroxy, nitro, thio, alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, alkoxy, aryloxy, sulfoxy, sulfinyl, sulfonyl, N-sulfonylcarboxyamido, and N-acylaminosulfonyl. Examples of aryl groups include phenyl, 2,4-dichlorophenyl, naphthyl, biphenyl, terphenyl. xe2x80x9cHeteroarylxe2x80x9d embraces aromatic radicals that contain one to four hetero atoms selected from oxygen, nitrogen and sulfur in a single or fused heterocyclic ring system, having from five to fifteen ring members. One or more hydrogen atoms may also be replaced by a substituent group selected from acyl, amino, acylamino, acyloxy, carboalkoxy, carboxy, carboxyamido, cyano, halo, hydroxy, nitro, thio, alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, alkoxy, aryloxy, sulfoxy, sulfinyl, sulfonyl, N-sulfonylcarboxyamido, and N-acylaminosulfonyl. Examples of heteroaryl groups include, tetrazolyl, pyridinyl, thiazolyl, thiadiazoyl, isoquinolinyl, pyrazolyl, oxazolyl, oxadiazoyl, triazolyl, and pyrrolyl groups.
The term xe2x80x9ccycloalkylxe2x80x9d is defined as a saturated or partially unsaturated carbocyclic ring in a single or fused carbocyclic ring system having from three to twelve ring members. One or more hydrogen atoms may also be replaced by a substituent group selected from acyl, amino, acylamino, acyloxy, carboalkoxy, carboxy, carboxyamido, cyano, halo, hydroxy, nitro, thio, alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, alkoxy, aryloxy, sulfoxy, sulfinyl, sulfonyl, N-sulfonylcarboxyamido, and N-acylaminosulfonyl. Examples of a cycloalkyl group include cyclopropyl, cyclobutyl, cyclohexyl, and cycloheptyl. The term xe2x80x9cheterocyclylxe2x80x9d embraces a saturated or partially unsaturated ring containing zero to four hetero atoms selected from oxygen, nitrogen and sulfur in a single or fused heterocyclic ring system having from three to twelve ring members. One or more hydrogen atoms may also be replaced by a substituent group selected from acyl, amino, acylamino, acyloxy, carboalkoxy, carboxy, carboxyamido, cyano, halo, hydroxy, nitro, thio, alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl, aryl, heteroaryl, alkoxy, aryloxy, sulfoxy, sulfinyl, sulfonyl, N-sulfonylcarboxyamido, and N-acylaminosulfonyl. Examples of a heterocyclyl group include morpholinyl, piperidinyl, and pyrrolidinyl. The term xe2x80x9calkoxyxe2x80x9d denotes oxy-containing radicals substituted with an alkyl, cycloalkyl or heterocyclyl group. Examples include methoxy, tert-butoxy, benzyloxy and cyclohexyloxy. Preferred alkoxy radicals are xe2x80x9clower alkoxyxe2x80x9d radicals having a lower alkyl substituent. The term xe2x80x9caryloxyxe2x80x9d denotes oxy-containing radicals substituted with an aryl or heteroaryl group. Examples include phenoxy. The term xe2x80x9csulfinylxe2x80x9d is defined as a tetravalent sulfur radical substituted with an oxo substituent and a second substituent selected from the group consisting of alkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl. The term xe2x80x9csulfonylxe2x80x9d is defined as a hexavalent sulfur radical substituted with two oxo substituents and a third substituent selected from alkyl, cycloalkyl, heterocyclyl, aryl and heteroaryl. The term xe2x80x9cN-acylaminosulfonylxe2x80x9d denotes a hexavalent sulfur atom bound to two oxo substituents and an N-acyl-substituted amino group.
The pharmaceutically-acceptable salts of the compounds of the invention (preferably a compound of Formula I) include acid addition salts and base addition salts. The term xe2x80x9cpharmaceutically-acceptable saltsxe2x80x9d embraces salts commonly used to form alkali metal salts and to form addition salts of free acids or free bases. The nature of the salt is not critical, provided that it is pharmaceutically-acceptable. Suitable pharmaceutically-acceptable acid addition salts of the compounds of the invention (preferably a compound of Formula I) may be prepared from an inorganic acid or an organic acid. Examples of such inorganic acids are hydrochloric, hydrobromic, hydroiodic, nitric, carbonic, sulfuric and phosphoric acid. Appropriate organic acids may be selected from aliphatic, cycloaliphatic, aromatic, arylaliphatic, heterocyclic, carboxylic and sulfonic classes of organic acids, examples of which are formic, acetic, propionic, succinic, glycolic, gluconic, maleic, embonic (pamoic), methanesulfonic, ethanesulfonic, 2-hydroxyethanesulfonic, pantothenic, benzenesulfonic, toluenesulfonic, sulfanilic, mesylic, cyclohexylaminosulfonic, stearic, algenic, xcex2-hydroxybutyric, malonic, galactic, and galacturonic acid. Suitable pharmaceutically-acceptable base addition salts of compounds of the invention (preferably a compound of Formula I) include, but are not limited to, metallic salts made from aluminum, calcium, lithium, magnesium, potassium, sodium and zinc or organic salts made from N,Nxe2x80x2-dibenzylethylenediamine, chloroprocaine, choline, diethanolamine, ethylenediamine, N-methylglucamine and procaine. All of these salts may be prepared by conventional means from the corresponding compound of the invention (preferably a compound of Formula I) by treating, for example, the compound of the invention (preferably a compound of Formula I) with the appropriate acid or base.
As used herein, xe2x80x9ctreatingxe2x80x9d means preventing the onset of, slowing the progression of, or eradicating the existence of the condition being treated, such as a microbial infection. Successful treatment is manifested by a reduction and, preferably, an eradication of the bacterial and/or fungal infection in the subject being treated.
The compounds of the invention (preferably compounds of Formula I) can possess one or more asymmetric carbon atoms and are thus capable of existing in the form of optical isomers as well as in the form of racemic or non-racemic mixtures thereof. The compounds of the invention (preferably compounds of Formula I) can be utilized in the present invention as a single isomer or as a mixture of stereochemical isomeric forms. Diastereoisomers can be separated by conventional means such as chromatography, distillation, crystallization or sublimation. The optical isomers can be obtained by resolution of the racemic mixtures according to conventional processes, for example by formation of diastereoisomeric salts by treatment with an optically active acid or base. Examples of appropriate acids are tartaric, diacetyltartaric, dibenzoyltartaric, ditoluoyltartaric and camphorsulfonic acid. The mixture of diastereomers can be separated by crystallization followed by liberation of the optically active bases from these salts. An alternative process for separation of optical isomers includes the use of a chiral chromatography column optimally chosen to maximize the separation of the enantiomers. Still another available method involves synthesis of covalent diastereoisomeric molecules by reacting compounds of the invention (preferably compounds of Formula I) with an optically pure acid in an activated form or an optically pure isocyanate. The synthesized diastereoisomers can be separated by conventional means such as chromatography, distillation, crystallization or sublimation, and then hydrolyzed to obtain the enantiomerically pure compound. The optically active compounds of the invention (preferably compounds of Formula I) can likewise be obtained by utilizing optically active starting materials. These isomers may be in the form of a free acid, a free base, an ester or a salt.
The invention also embraces isolated compounds. An isolated compound refers to a compound which represents at least 10%, preferably 20%, more preferably 50% and most preferably 80% of the compound present in the mixture, and exhibits a detectable (i.e. statistically significant) antimicrobial activity when tested in conventional biological assays such as those described herein.
II. Description
According to one aspect of the invention, compounds of Formula I are provided. The compounds are useful for inhibiting the enzymatic activity of a tRNA synthetase in vivo or in vitro. The compounds are particularly useful as antimicrobial agents, i. e., agents that inhibit the growth of bacteria or fungi.
One sub-class of compounds of Formula I are compounds of Formula II 
wherein substituents R1, R2, R3, R4, R11, R12, R13, and R14 are as previously described.
The compounds of the invention (preferably compounds of Formula I) are active against a variety of bacterial organisms. They are active against both Gram positive and Gram negative aerobic and anaerobic bacteria, including Staphylococci, for example S. aureus; Enterococci, for example E. faecalis; Streptococci, for example S. pneumoniae; Haemophilus, for example H. influenza; Moraxella, for example M. catarrhalis; and Escherichia, for example E. coli. The compounds of the present invention (preferably compounds of Formula I) are also active against Mycobacteria, for example M. tuberculosis. The compounds of the present invention (preferably compounds of Formula I) are also active against intercellular microbes, for example Chlamydia and Rickettsiae. The compounds of the present invention (preferably compounds of Formula I) are also active against Mycoplasma, for example M. pneumoniae. 
The compounds of the present invention (preferably compounds of Formula I) are also active against fungal organisms, including, among other organisms, the species Aspergillus, Blastomyces, Candida, Coccidioides, Cryptococcus, Epidermophyton, Hendersonula, Histoplasma, Microsporum, Paecilomyces, Paracoccidioides, Pneumocystis, Trichophyton, and Trichosporium.
In a second aspect the invention provides a pharmaceutical composition comprising a compound of the invention, preferably a compound in accordance with the first aspect of the invention, and a pharmaceutically-acceptable carrier (described below). As used herein the phrase xe2x80x9ctherapeutically-effective amountxe2x80x9d means that amount of a compound of the present invention (preferably a compound of Formula I) which prevents the onset of, alleviates the symptoms of, or stops the progression of a microbial infection. The term xe2x80x9cmicrobialxe2x80x9d means bacterial and fungal, for example a xe2x80x9cmicrobial infectionxe2x80x9d means a bacterial or fungal infection. The term xe2x80x9ctreatingxe2x80x9d is defined as administering, to a subject, a therapeutically-effective amount of a compound of the invention (preferably a compound of Formula I). The term xe2x80x9csubjectxe2x80x9d, as described herein, is defined as a mammal, a plant or a cell culture.
According to another aspect of the invention, a method for inhibiting a tRNA synthetase is provided which comprises contacting a tRNA synthetase with a compound of the invention (preferably a compound of Formula I) under the conditions whereby the tRNA synthetase interacts with its substrates and its substrates react(s) to form an aminoacyl adenylate intermediate and, preferably, react(s) further to form a charged tRNA. Such conditions are known to those skilled in the art (see also e. g., the Examples for conditions), and PCT/US 96/11910, filed Jul. 8, 1996 (WO 97/05132, published Feb. 3, 1997), and U.S. Pat. No. 5,726,195. This method involves contacting a tRNA synthetase with an amount of compound of the invention (preferably a compound of Formula I) that is sufficient to result in detectable tRNA synthetase inhibition. This method can be performed on a tRNA synthetase that is contained within an organism or outside an organism.
In a further aspect, the invention provides a method for inhibiting the growth of microorganisms, preferably bacteria or fungi, comprising contacting said organisms with a compound of the invention (preferably a compound of Formula I) under conditions which permit entry of the compound into said organism and into said microorganism. Such conditions are known to one skilled in the art and are exemplified in the Examples. This method involves contacting a microbial cell with a therapeutically-effective amount of compound(s) of the invention (preferably compound(s) of Formula I), e.g. to inhibit cellular tRNA synthetase in vivo or in vitro. This method is used in vivo, for example, for treating microbial infections in mammals. Alternatively, the method is used in vitro, for example, to eliminate microbial contaminants in a cell culture, or in a plant.
In accordance with another aspect of the invention, the compositions disclosed herein are used for treating a subject afflicted by or susceptible to a microbial infection. The method involves administering to the subject a therapeutically effective amount of a compound of the invention (preferably a compound of Formula I). According to this aspect of the invention, the novel compositions disclosed herein are placed in a pharmaceutically acceptable carrier and are delivered to a recipient subject (preferably a human) in accordance with known methods of drug delivery. Exemplary procedures for delivering an antibacterial, antifungal and antimycoplasmal agent are described in U.S. Pat. No. 5,041,567, issued to Rogers and in PCT patent application number EP94/02552 (publication no. WO 95/05384), the entire contents of which documents are incorporated in their entirety herein by reference. In general, the methods of the invention for delivering the compositions of the invention in vivo utilize art-recognized protocols for delivering the agent with the only substantial procedural modification being the substitution of the compounds of the invention (preferably compounds of Formula I) for the drugs in the art-recognized protocols. Likewise, the methods for using the claimed composition for treating cells in culture, for example, to eliminate or reduce the level of bacterial contamination of a cell culture, utilize art-recognized protocols for treating cell cultures with antibacterial agent(s) with the only substantial procedural modification being the substitution of the compounds of the invention (preferably compounds of Formula I) for the agents used in the art-recognized protocols.
The pharmaceutical preparations disclosed herein are prepared in accordance with standard procedures and are administered at dosages that are selected to reduce, prevent or eliminate the infection (See, e. g., Remington""s Pharmaceutical Sciences, Mack Publishing Company, Easton, Pa. and Goodman and Gilman""s The Pharmaceutical Basis of Therapeutics, Pergamon Press, New York, N.Y., the contents of which are incorporated herein by reference, for a general description of the methods for administering various antimicrobial agents for human therapy). The compositions of the invention (preferably of Formula I) can be delivered using controlled ( e.g., capsules) or sustained release delivery systems (e.g., bioerodable matrices). Exemplary delayed release delivery systems for drug delivery that are suitable for administration of the compositions of the invention (preferably of Formula I) are described in U.S. Pat. No. 4,452,775 (issued to Kent), U.S. Pat. No. 5,239,660 (issued to Leonard), U.S. Pat. No. 3,854,480 (issued to Zaffaroni).
The pharmaceutically-acceptable compositions of the present invention comprise one or more compounds of the invention (preferably compounds of Formula I) in association with one or more nontoxic, pharmaceutically-acceptable carriers and/or diluents and/or adjuvants and/or excipients, collectively referred to herein as xe2x80x9ccarrierxe2x80x9d materials, and if desired other active ingredients.
The compounds of the present invention (preferably compounds of Formula I) are administered by any route, preferably in the form of a pharmaceutical composition adapted to such a route, as illustrated below and are dependent on the condition being treated. The compounds and compositions can be, for example, administered orally, intravascularly, intraperitoneally, subcutaneously, intramuscularly or topically.
For oral administration, the pharmaceutical compositions are in the form of, for example, a tablet, capsule, suspension or liquid. The pharmaceutical composition is preferably made in the form of a dosage unit containing a therapeutically-effective amount of the active ingredient. Examples of such dosage units are tablets and capsules. For therapeutic purposes, the tablets and capsules which can contain, in addition to the active ingredient, conventional carriers such as binding agents, for example, acacia gum, gelatin, polyvinylpyrrolidone, sorbitol, or tragacanth; fillers, for example, calcium phosphate, glycine, lactose, maize-starch, sorbitol, or sucrose; lubricants, for example, magnesium stearate, polyethylene glycol, silica, or talc; disintegrants, for example, potato starch, flavoring or coloring agents, or acceptable wetting agents. Oral liquid preparations generally are in the form of aqueous or oily solutions, suspensions, emulsions, syrups or elixirs may contain conventional additives such as suspending agents, emulsifying agents, non-aqueous agents, preservatives, coloring agents and flavoring agents. Examples of additives for liquid preparations include acacia, almond oil, ethyl alcohol, fractionated coconut oil, gelatin, glucose syrup, glycerin, hydrogenated edible fats, lecithin, methyl cellulose, methyl or propyl para-hydroxybenzoate, propylene glycol, sorbitol, or sorbic acid.
The pharmaceutical compositions can be administered via injection. Formulations for parenteral administration can be in the form of aqueous or non-aqueous isotonic sterile injection solutions or suspensions. These solutions or suspensions can be prepared from sterile powders or granules having one or more of the carriers mentioned for use in the formulations for oral administration. The compounds can be dissolved in polyethylene glycol, propylene glycol, ethanol, corn oil, benzyl alcohol, sodium chloride, and/or various buffers.
For topical use the compounds of the present invention can also be prepared in suitable forms to be applied to the skin, or mucus membranes of the nose and throat, and can take the form of creams, ointments, liquid sprays or inhalants, lozenges, or throat paints. Such topical formulations further can include chemical compounds such as dimethylsulfoxide (DMSO) to facilitate surface penetration of the active ingredient.
For application to the eyes or ears, the compounds of the present invention can be presented in liquid or semi-liquid form formulated in hydrophobic or hydrophilic bases as ointments, creams, lotions, paints or powders.
For rectal administration the compounds of the present invention can be administered in the form of suppositories admixed with conventional carriers such as cocoa butter, wax or other glyceride.
Alternatively, the compounds of the present invention can be in powder form for reconstitution in the appropriate pharmaceutically acceptable carrier at the time of delivery.
The dosage regimen for treating an infection with the compound and/or compositions of this invention is selected in accordance with a variety of factors, including the type, age, weight, sex and medical condition of the patient, the severity of the infection, the route and frequency of administration and the particular compound employed. In general, dosages are determined in accordance with standard practice for optimizing the correct dosage for treating an infection.
The compositions can contain from 0.1% to 99% by weight, preferably 10-60% by weight, of the active ingredient, depending on the method of administration. If the compositions contain dosage units, each dosage unit preferably contains from 50-500 mg of the active material. For adult human treatment, the dosage employed preferably ranges from 100 mg to 3 g, per day, depending on the route and frequency of administration.
If administered as part of a total dietary intake, the amount of compound employed can be less than 1% by weight of the diet and preferably no more than 0.5% by weight. The diet for animals can be normal foodstuffs to which the compound can be added or it can be added to a premix.